Chemical Vapour Deposition (CVD) of wear resistant coatings on cemented carbide cutting tools has been in industrial practice for many years. Coatings such as TiCN and Al2O3 have shown to improve the wear resistance on cutting inserts in cutting of many different materials. A combination on an inner layer of TiCN and an outer layer of α-Al2O3 can be found on many commercial cutting inserts designed for turning of, for example, steel.
EP1905870A2 discloses a coated cutting insert comprising a coating with at least one α-Al2O3 layer showing a strong growth texture along <0 0 1>. The edge toughness of the insert was improved in turning.